/**
 * @param {character[][]} board
 * @param {string} word
 * @return {boolean}
 */
 var exist = function(board, word) {
  for(let i=0;i<board.length;i++){
    for(let j=0;j<board[i].length;i++){
      for(let k=0;k<word.length;k++){
        if()
      }
    }
  }
};